Cost reduction in sugar industries can be achieved just by adjusting and optimizing structures and/or key process variables to assure maximum use of the sugar formed in the field. The evaporation section is the critical stage for efficient management of water and energy resources. Thus, the selected case study addresses the optimization of the operation of continuous evaporation units working in parallel and presenting a decrease of in efficiency with time. The problem was solved through mathematical programming that obtained optimum values for the operating variables. Therefore, it was necessary to mathematically formulate the optimization problem and to model the operations under study. A mixed integer nonlinear programming model (MINLP) was used in order to meet the targets. Also, a technical objective function with economical background was developed. The industrial implementation required as well the conception and development of a user-friendly decision-making tool to facilitate the routine work and to allow plant managers to check, accept, and put into practice the solution proposed. The application of the presented strategies to an industrial case study demonstrates the efficiency and potential of the approach adopted.